sizeFollowsWindow=false in qtwayland compositor causes qtwebengine to crash/malfunction

Hi

I got qtwayland based compositor and a browser based on webengine.

My target is a Linux based ARM64 device.

I got a a few different problems, that seem to be related to sizeFollowsWindow in qtwayland, but seen when using a browser based on webengine.

Problem 1 - select dropdown malfunction:

Select dropdowns does not work if sizeFollowsWindow is not set.

Attached 3 files to test the problem:

• compositor.qml - a minimal compositor

• demo.html - a html page that just a select dropdown

• demo.qml - a webengine browser that points to demo.html
  compositor.qmldemo.qmldemo.html

With sizeFollowsWindow, the select dropdown is shown perfectly fine

When sizeFollowsWindow is set to false, then the select dropdown is not expanded when pressed, and hence looks like this:

Problem 2 - memory leak

Setting sizeFollowsWindow to true and setting the url to:

https://e.infogram.com/dfc9a09d-0066-48a7-9288-f3e1ef525af9?parent_url=about%3Asrcdoc&src=embed

Page is shown perfectly fine:

If instead setting sizeFollowsWindow to false, webengine will leak memory and crash the system in a couple of minutes.